STOCKHOLM INTERNATIONAL
PEACE RESEARCH INSTITUTE

New SIPRI Publication:
07 June 2023

The Role of Umbrella States in the Global Nuclear Order

Today, SIPRI releases a paper that assesses the scope of umbrella states’ agency in maintaining, shaping and potentially challenging the global nuclear status quo.

Download the SIPRI Insights Paper here.

This paper focuses on countries under extended nuclear deterrence arrangements, or ‘umbrella’ states. The paper explores the ways in which umbrella states both in the Asia-Pacific region and in Europe have supported prevailing nuclear deterrence practices or distanced themselves from such practices.

While there is a tendency for these countries to side with their nuclear-armed patron on matters related to nuclear weapons and nuclear disarmament norms, at times they have taken steps away from the allied mainstream position by advocating for anti-nuclear weapon policies. As long as extended deterrence has a nuclear dimension, allies will need to balance between normative pressures to support nuclear disarmament and alliance commitments that require at least passive support for nuclear deterrence practices.

About the author

Tytti Erästö (Finland) is a Senior Researcher in the SIPRI Weapons of Mass Destruction Programme, focusing on nuclear disarmament and non-proliferation issues. 

For information and interview requests contact Amelie Lutz, SIPRI Communications Officer, (amelie.lutz@sipri.org, +46 76 628 61 33).